Question

The mass of a 50-mL volumetric flask is 40.638 g. After adding 15.0 mL of 95% ethanol and adding enough water to complete the volume to 50.00 mL, the flask weighed 88.219 g. What is the density of the mixture?

Answer 1

To find the mixture's density, subtract the volumetric flask's mass from the total mass to find the solution's mass, then divide by the volume of the mixture, resulting in a density of 0.9516 g/mL.

Step-by-step explanation:

The student is asking for the calculation of the density of a mixture of ethanol and water. To determine the density, we first calculate the mass of the solution by subtracting the mass of the empty flask from the filled flask's mass. We then divide this mass by the volume of the solution.

Step-by-Step Solution:

1. Calculate the mass of the solution: 88.219 g (filled flask) - 40.638 g (empty flask) = 47.581 g (mass of the solution).
2. Since we know the volume of the solution is 50.00 mL, divide the mass of the solution by this volume to find the density: density = mass / volume = 47.581 g / 50.00 mL = 0.9516 g/mL.

Thus, the density of the mixture is 0.9516 g/mL.

Answer 2

0.9516 grams / mL (50.00 has 4 sig digs.)

Remark

You have a couple of extraneous numbers there. You don't care about anything except the mass of the flask + water/alcohol mixture (88.219 grams). and the mass of the flask (40.638 grams)

Formulas

• mass water/alcohol mixture = mass of the flask with fluid - mass flask
• density = mass / volume

Solution

mass water/alcohol mixture = 88.219 - 40.638 = 47.581

• Volume = 50 mL
• Density = mass / Volume
• Density = 47.581/50
• Density = 0.95162 There are 4 sig digs so the answer should be
• 0.9516